Submission #526567

#	Time	Username	Problem	Language	Result	Execution time	Memory
526567		kaxzert	Harbingers (CEOI09_harbingers)	C++17	70 / 100	1066 ms	25604 KiB

harbingers

/**
      ⚡⚡  ⚡⚡      ⚡⚡⚡     ⚡⚡  ⚡⚡  ⚡⚡⚡⚡⚡⚡   ⚡⚡⚡⚡⚡  ⚡⚡⚡⚡⚡⚡  ⚡⚡⚡⚡⚡⚡
      ⚡⚡ ⚡⚡      ⚡⚡⚡⚡     ⚡⚡⚡⚡      ⚡⚡      ⚡⚡       ⚡⚡    ⚡⚡  ⚡⚡⚡⚡⚡⚡
      ⚡⚡⚡⚡      ⚡⚡  ⚡⚡      ⚡⚡      ⚡⚡       ⚡⚡⚡⚡⚡   ⚡⚡⚡⚡⚡⚡     ⚡⚡
      ⚡⚡ ⚡⚡    ⚡⚡⚡⚡⚡⚡     ⚡⚡     ⚡⚡         ⚡⚡       ⚡⚡  ⚡⚡       ⚡⚡
      ⚡⚡  ⚡⚡  ⚡⚡     ⚡⚡  ⚡⚡ ⚡⚡  ⚡⚡⚡⚡⚡⚡  ⚡⚡⚡⚡⚡    ⚡⚡   ⚡⚡     ⚡⚡
**/

#include<bits/stdc++.h>

using namespace std;

#define fto(i, a, b) for(int i = a; i <= b; ++i)
#define fdto(i, a, b) for(int i = a; i >= b; --i)
#define bugarr(a, i, j) cout << #a << "{" << i << "..." << j << "}:"; fto(k, i, j-1) cout << a[k] << ", "; cout << a[j] << endl;
#define ll long long
#define db double
#define ldb long double
#define ff first
#define ss second
#define pb push_back
#define mp make_pair
#define eb emplace_back
#define vt vector
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define trav(i, a) for(auto &i : a)
#define sz(a) (int)a.size()
#define pi(a, b) pair<a, b>
#define fast ios::sync_with_stdio(false); cin.tie(0)

void setIO(string s) {
    if (sz(s) != 0) {
        freopen((s+".inp").c_str(),"r",stdin);
        freopen((s+".out").c_str(),"w",stdout);
    }
}

void setIOusaco(string s) {
    if (sz(s) != 0) {
        freopen((s+".in").c_str(),"r",stdin);
        freopen((s+".out").c_str(),"w",stdout);
    }
}

template<typename T, typename V>
bool ckmin(T &a, V b) {return (b < a)? a = b, true : false;}
template<typename T, typename V>
bool ckmax(T &a, V b) {return (b > a)? a = b, true : false;}

//        a     x      b      c      c    c
// f[i] = -d[j]*v[i] + f[j] + s[i] + d[i]*v[i]

const int maxN = 100008;
ll s[maxN], v[maxN], f[maxN];
vt<pair<int, ll> > ke[maxN];

struct line {
	ll a, b;
	line(ll a, ll b):a(a), b(b){}

	ll intersect(line o) {
		ll x = o.b - b;
		ll y = a - o.a;
		return (x+y-1)/y;
	}

	ll val(ll x) {
		return a*x + b;
	}
};
vt<pair<line, ll> > lines;

ll query2(ll x) {
	auto pos = *lower_bound(rall(lines), mp(line(0, 0), x), [=](pair<line, ll> a, pair<line, ll> b) {
		return a.ss > b.ss;
	});
	return pos.ff.val(x);
}

void dfs(int u, int p = 0, ll d = 0) {
	if (u != 1) {
		f[u] = query2(v[u]) + s[u] + d*v[u];
	}
	vt<pair<line, ll> > res;
	line newline(-d, f[u]);
	while(!lines.empty() && lines.back().ss >= lines.back().ff.intersect(newline)) {
		res.pb(lines.back());
		lines.pop_back();
	}
	lines.eb(newline, (lines.empty() ? 0 : lines.back().ff.intersect(newline)));
	for(auto [v, w] : ke[u]) {
		if (v == p) continue;
		dfs(v, u, d+w);
	}
	assert(!lines.empty());
	lines.pop_back();
	reverse(all(res));
	trav(u, res) lines.pb(u);
}

int main() {
    #ifndef TAP 
    setIO("");
    //setIOusaco("harbingers");
    #endif

    fast;
    int n;
    cin >> n;
    fto(i, 1, n-1) {
    	int u, v;
    	ll w;
    	cin >> u >> v >> w;
    	ke[u].eb(v, w);
    	ke[v].eb(u, w);
    }

    fto(i, 2, n) {
    	cin >> s[i] >> v[i];
    }

    f[1] = 0;
    dfs(1);

    fto(i, 2, n) cout << f[i] << " \n"[i==n];

    return 0;
}

Compilation message (stderr)

harbingers.cpp: In function 'void setIO(std::string)':
harbingers.cpp:34:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   34 |         freopen((s+".inp").c_str(),"r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
harbingers.cpp:35:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   35 |         freopen((s+".out").c_str(),"w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
harbingers.cpp: In function 'void setIOusaco(std::string)':
harbingers.cpp:41:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   41 |         freopen((s+".in").c_str(),"r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
harbingers.cpp:42:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   42 |         freopen((s+".out").c_str(),"w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 70 / 100